The present invention I relates to a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones in which there is decreased the amount of adducts containing two or more continuous lactone chains, a method for the preparation thereof, and an acrylic polyol resin which can be employed as an industrial finishing agent having a high quality and which is variously well-balanced, for example, coatings and a pressure-sensitive adhesive, an ultraviolet ray- or electron beam-curable coating agent, and a reactive modifier.
Further, the present invention II relates to a method for the preparation of a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones.
Still further, the present invention III relates to a curable resin composition comprising an acrylic polyol resin containing the hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as a polymerizable component and a melamine resin, by which there can be prepared a coating having an improved acid resistance and being well-balanced in abrasion resistance and an acid resistance.
Furthermore, the present invention IV relates to a melamine-curable type water-based coating composition comprising the acrylic polyol resin containing the hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones and an amino-plasto resin, and which is appropriate as a water-based coating for cars, home electric appliances, and cans for beverages and foods, particularly, which is appropriate as a clear coating for finishing an outer surface of cans.
In addition, the present invention V relates to a curable resin composition containing an acrylic polyol resin obtained by employing the hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones in which there are decreased adducts containing two or more continuous lactone chains and a polyisocyanate compound as essential components, by which there can be prepared a coating having a long pot life and an excellent abrasion resistance and water resistance.
Also, the present invention VI relates to a coating containing a curable resin composition and crosslinked particles obtained from the curable resin composition or urethane-urea/ethylenic resin-composite type crosslinked particles as essential coating layer-formable components. The curable resin composition essentially contains a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones and a polyisocyanate compound as essential components. The hydroxyalkyl(meth)acrylate composition is a vinyl-based copolymer having carboxylic group and a crosslinkable functional group. The vinyl-based copolymer is obtained by allowing to react the hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones with a carboxylic group-contained vinyl-based monomer and other vinyl-based monomers.
The vinyl-based copolymer is the acrylic polyol resin (A) in the curable resin composition of the present invention V.
And also, the present invention VII relates to a thermosetting resin composition comprising an acrylic polyol resin containing the hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones and an alkoxysilyl group-contained acrylic copolymer, and relates to a top-coat clear coating primarily containing the thermosetting resin composition, and which is employed as an outer coating for buildings, a variety of coatings for cars, industrial machines, a steel-made furniture, home electric appliances, and plastics, in which durability is particularly required.
Besides, the present invention VIII relates to a carboxylic group-contained acrylate modified by a small amount of lactones which is useful as a raw material for resins.
Also, the present invention IX relates to a curable resin composition, a clear coating composition, and a method for coating, and the curable resin composition is employed as a finishing coating for cars and coil coating, etc., which is composed of an acrylic polycarboxylic acid resin containing a carboxylic group-contained acrylate monomer modified by a small amount of lactones and a polyepoxide.
And also, the present invention X relates to a polyester unsaturated monomer composition modified by a small amount of lactones, a method for the preparation thereof, and an acrylic resin prepared therefrom which does not show tackiness.
By allowing to react these monomer compositions with other ethylenic unsaturated monomer and formulating with a variety of crosslinking agents and other components which are usually employed, there can be prepared an industrial finishing agent which is variously well-balanced, for example, a coating, an pressure-sensitive adhesive, an ultraviolet ray- or electron beam-curable coating agent, a curable oligomer and a polymer which can be employed as a reactive modifier, etc.
In recent years, there has been raised an importance of an acrylic-based coating in a coating field.
It is a reason that it has an excellent characteristic in weatherability, chemical resistance, and staining resistance, etc. compared to other alkyd resins, polyester resins, and epoxy resins.
For that reason, an acrylic-based coating has been employed in many fields such as cars, home electric appliances, metals, and construction materials.
Of acrylic resins, an acrylic polyol in which a monomer having hydroxyl group is copolymerized is applied as an ordinary temperature-curable coating or a baking-curable coating in which there is formulated a crosslinking agent which is capable of reacting with hydroxyl group, for example, a polyisocyanate and a melamine resin, etc. The monomer having hydroxyl group is indispensable in order to give adhesion to a coating layer and a gasoline resistance.
As the monomer having hydroxyl group, there have been conventionally employed a hydroxyethyl(meth)acrylate and hydroxypropyl(meth)acrylate, etc. Herein, the (meth)acrylate means an acrylate and a methacrylate.
However, hydroxyl groups in an acrylic polyol prepared by copolymerization of the monomers do not show a sufficient reactivity with the crosslinking agent because it is situated in a position which is exceedingly near by a main chain of a rigid acrylic resin skeleton.
For the purpose of improvement thereof, although 4-hydroxybutylacrylate is proposed, it is difficult to say that reactivity thereof is sufficient.
In order to solve problems, there has been employed a means for synthesizing a lactone-modified acrylic polyol in which xcex5-caprolactone is allowed to addition-react to a hydroxyalkylacrylate or a hydroxalkylmethacrylate, followed by copolymerizing with other monomers.
By the means, although reactivity with the crosslinking agent and ductility can be solved, a distribution of lactone continuous chains is broad in a conventional lactone-modified (meth)acrylate, and the number (n) of the lactone continuous chains becomes large and, whereby, although curing reactivity and ductility are improved, there is occasionally caused a problem that there lower hardness and acid resistance, etc.
For example, in the case that there is employed a hydroxyalkylacrylate or a hydroxyalkylmethacrylate having the large number of the lactone continuous chain in which xcex5-caprolactone is added as a raw material in a top-coat coating for cars, since a hydroxyl value per the unit weight of a product becomes lower, a large amount of the acrylate or methacrylate must be employed in order to adjust the hydroxyl value, whereby, there are occasionally deteriorated other requiring items such as a glossiness and an acid resistance other than the abrasion resistance.
Further, although it is occasionally controlled using a hydroxyethylacrylate or hydroxyethylmethacrylate in order to adjust the hydroxyl value without feeding a large amount of a lactone-modified hydroxyalkylacrylate or hydroxyalkyl methacrylate, in the case, there becomes smaller a proportion of a hydroxyalkyl(meth)acrylate containing 1 mol of the lactone single chain in which the number of xe2x80x9cnxe2x80x9d is 1, in which ductility and hardness are well-balanced.
In a coating layer for cars, it is looked upon that there are problematic a durability of the coating layer, particularly, blurs by acidic rain, scratches caused by sand particles which are blown up by a washing brush and by running. For example, a clear coat which is an over-coating in a car body is often composed of an acrylic resin and a melamine resin, and it becomes clear that the melamine resin causes a problem of decline in the acid resistance and, there are proposed (JP-A-63221123 Official Gazette and JP-A-63108048 Official Gazette) coatings by a novel crosslinking style not containing the melamine resin. However, the coatings are higher in price compared to a melamine-based thermosetting coating, and include a problem that those are poor in adhesion to the melamine-based thermosetting coating.
Of the acrylic resins, an acrylic polyol in which there is copolymerized a monomer having hydroxyl group is employed in an ordinary temperature-curable or thermosetting-curable coating in which there is formulated a crosslinking agent which can react with hydroxyl group, for example, such as a polyisocyanate and a melamine resin. In order to give an adhesion to a coating layer and a gasoline resistance, acrylic monomers having hydroxyl group are indispensable.
As such the monomers having hydroxyl group, there have been conventionally employed a hydroxyethyl(meth)acrylate and a hydroxypropyl(meth)acrylate, etc.
However, since the hydroxyl group in an acrylic polyol prepared by copolymerization of the (meth)acrylates is situated in an exceedingly near position to a main chain of an acrylic resin structure which is rigid, a reactivity with the crosslinking agent is not sufficient.
For the purpose of improvement thereof, although 4-hydroxybutylacrylate is proposed, it is difficult to say that a reactivity thereof is sufficient.
As a method for solving such the problems, in relation to a abrasion resistance, for example, there has been conventionally known (JP-A-64066274 Official Gazette) a coating using a clear coat in which there are employed an xcex5-caprolactone-modified acrylic resin obtained by copolymerization of an xcex5-caprolactone-added hydroxyalkyl(meth)acrylate with other vinyl monomers and a melamine curing agent and, further, for an acidic rain, for example, there has been conventionally known (JP-A-04114069 Official Gazette) a coating using a clear coat in which there are simultaneously employed a reaction of carboxylic acid with an epoxy and a reaction of an acrylic resin with a melamine curing agent.
However, since the lactone-modified (meth)acrylate in a technology of the JP-A-64066274 Official Gazette has a broad distribution of continuous lactone chains and the number (n) of the continuous lactone chains is large, there is occasionally caused the above-described problem that although curing reactivity and flexibility are improved, there lower hardness and acid resistance, etc.
On the other hand, although there is obtained a coating layer having an excellent acid resistance in a technology of the JP-A-04114066 Official Gazette, abrasion resistance is insufficient.
Further, there has been known that it is an effective method to elevate a glass transition temperature in a cured coating layer formed from a clear coat which is a most outside surface layer in order to obtain an advanced acid resistance. However, in the case, there has been a problem that there is caused an unpreferred situation that there lower not only the abrasion resistance in the coating layer but also flexural resistance and adhesion in recoating. Accordingly, it has been an exceedingly difficult technology to obtain a coating layer which is highly well-balanced in the acid resistance and abrasion resistance, and which is also excellent in the flexural resistance and adhesion in recoating.
Metal cans have been widely employed as a vessel for filling a variety of beverages and foods.
Outside surface of the cans is coated in order to prevent corrosion by outside circumstances, and printed in view of a fine sight, and for showing contents. In printing and coating of the outside surface of the cans, a size-coating is coated on a metal plate, and then, a white coating is coated and, printing is conducted thereon by inks, etc. and a clear coating is coated for finishing. The size-coating and white coating are also occasionally omitted. Hitherto, as the clear coating for finishing, there has been widely employed an organic solvent solution containing an acrylic/amino-based resin, a polyester/amino-based resin, and an epoxy/amino-based resin, etc.
JP-A-06207137 Official Gazette discloses a water-based coating for an outer surface of cans, which is a coating primarily containing a resin mixture composed of (A) 40-60 parts by weight of an acrylic resin having a specified composition which has a weight average molecular weight of 6,000-15,000 and a glass transition temperature of exceeding 0xc2x0 C., (B) 10-20 parts by weight of an acrylic resin having a specified composition which has a weight average molecular weight of 5,000-50,000 and a glass transition temperature of not more than 0xc2x0 C., and (C) 20-50 parts by weight of an amino-plasto resin, and the resins (A) and (B) are neutralized by a base and, the resins (A), (B), and (C) are dissolved or dispersed in water. However, a coating layer obtained from the above-described technology is not sufficient in hardness.
Publicly-known water-based coatings include two types of a water-dispersed type one and a water-soluble type one, and since the water-dispersed type one is usually synthesized by an emulsion polymerization method using a surface active agent, there has been a problem that the surface active agent remains in a coating layer after having formed the coating layer, and it causes a decline of water resistance. On the other hand, although there is also a method synthesizing a resin containing carboxylic groups in an organic solvent system without employing the surface active agent and making dipersible or water-soluble by neutralizing in a volatile base, the water-based coating requires an acidic component having an acid value of not less than 20 in a basic resin structure, and there has been a drawback of poor water resistance and alkali resistance, etc.
A variety of coatings have been proposed and, although there is observed an improvement of water resistance in a coating layer, properties are not in a level being resistible to a thermally sterilizing treatment (retorting) in 130xc2x0 C. for 30 minutes.
JP-A-07316489 Official Gazette discloses a water-based coating composition characterized by containing 20-80 parts by weight of a water-based acrylic resin obtained by copolymerization of (i) xcex1, xcex2-ethylenic unsaturated carboxylic acid, (ii) a hydroxyl group-contained mono(meth)acrylate including an xcex5-caprolactone-modified monomer, (iii) an N-alkoxymethyl(meth)acrylic amide having an alkyl group of a carbon number of not more than 4, and an aromatic vinyl monomer which is copolymerizable with the (i)-(iii) and/or an alkyl(meth)acrylate and 10-60 parts by weight of a water-based amino resin. However, water resistance is not sufficient in the coating composition obtained by the above-described technology.
Further, a water-based coating composition has been also employed for coating in cars and home electric appliances.
For example, in recent years, a design value in resin-made parts such as a bumper for cars is elevated by coating the same color as in car bodies. In the case of coating a bumper made from a polypropylene, etc. like a body color, there is firstly coated a primer made from a chlorinated polypropylene, etc. in order to ensure adhesion. A coating layer is formed by a two coating-one baking method (hereinafter, referred to as a 2C1B method) in which a coating layer of the primer is thermally cured and a coating for a base coat and an over coating are coated by a wet-on-wet method and those are thermally cured collectively.
However, there has become problematic a staining in a coating layer which is called a rain-blot under the influence of an acidic rain in recent years. Particularly, in a baked coating layer made from a melamine resin, it is known that an ether bond in the vicinity of melamine is broken by the acidic rain, and a stain penetrates therein, resulting in that it becomes difficult to remove the stain by a water-washing level. Accordingly, it must be rubbed off by a compound, etc. and, in the case, there is a problem that a coating layer is also shaved off, resulting in that the thickness of the coating layer becomes thinner.
Comparing a coating layer on an outside plate of cars to a coating layer on a bumper, the rain-blot is more readily caused in the coating layer on a bumper, there is a problem that the rain-blot once caused is not apt to be removed compared to the coating layer on an outside plate. It is thought that it depends upon a crosslinking density. In other words, since the coating layer on an outside plate is cured by heating conditions such as 140xc2x0 C. for 30 minutes or so, a crosslinking density is high. However, in the coating layer on a resin-made bumper, since heating temperature is suppressed in 120xc2x0 C. for 20 minutes or so in order to prevent deformation, a crosslinking density becomes lower compared to the coating layer on an outside plate for cars. For that reason, an acid rain resistance is not sufficient, and it is thought that the above-described difference is caused.
Therefore, it is thought that a blocked polyisocyanate compound is employed as a crosslinking agent without using a melamine resin. However, curability is poor at a low temperature in a coating composition in which the blocked polyisocyanate compound is employed as a crosslinking agent. For that reason, when the coating composition is coated on a resin-made bumper, etc., since heating temperature is 120xc2x0 C. to the utmost, crosslinking density is low, resulting in that there become insufficient physical properties such as solvent resistance, staining resistance, and water resistance.
JP-A-11012533 discloses a water-based coating composition comprising a neutralized product of an amino resin-modified polymer in which structural units based on the above-described component (a) in the copolymer composed of (a) radically polymerizable compound having a specified structural formula, (b) an xcex1,xcex2-ethylenic unsaturated carboxylic acid, and (c) other radically polymerizable monomers are modified by a reaction of hydroxyl group in the units with an amino resin. However, a coating layer from the composition is not sufficient in retort resistance.
As described hereinabove, in recent years, an acrylic-based coating is becoming important in a coating field and, in a coating layer for cars, durability of a coating layer, particularly, there become problematic a rain-blot by an acidic rain, abrasions by sand particles blown up by a washing brush and during driving, and the above-described various methods are proposed. However, there have still been the above-described various problems.
On the other hand, although an isocyanate curing system shows an excellent acid resistance, adhesion, water resistance, and hardness, there is a problem that a pot-life is shorter compared to a melamine coating and, crosslinking of a resin is insufficient, and abrasion resistance is lower in a coating layer. Although the abrasion resistance can be improved by employing a modified hydroxy(meth)acrylate, etc. (PCL F, etc.), a pot-life further becomes short by an existing PCL F having a long lactone continuous chain length, and there is caused a problem that it cannot become taken a working time of period.
For the above-described problems in an isocyanate curing system, JP-A-05148313 Official Gazette proposes a coating which possesses various properties such as profitability and workability without loss of a fine spectacle and, moreover, which can also satisfy a corrosion resistance, and which can provide a coating layer for a metal having an advanced corrosion resistance and, moreover, which primarily contains a coating layer-formable resinous component in which there are employed specified crosslinked particles which do not cause any problems in corrosion resistance even though a conventional melamine curing agent is employed. Although the abrasion resistance can be improved by employing a modified hydroxy(meth)acrylate, etc. (PCL F, etc.), the abrasion resistance, the improvement is insufficient by the PCL F having a long lactone continuous chain length.
In a conventional thermosetting coating, there has been employed a melamine resin such as an alkyd melamine resin, an acrylic melamine resin, and an epoxy melamine resin as a crosslinking agent, and an odor from the melamine resin has been largely problematic. Further, in an acrylic melamine resin and an alkyd melamine resin which are usually employed as a coating for cars, there are not always sufficiently satisfied properties such as weatherability, staining resistance, acidic resistance, and a water-repellent property, and an improvement thereof is strongly desired.
As a method for solving the problems, there is proposed a technology (JP-A-01141952 Official Gazette, etc.) concerning a composition which is cured by a crosslinking style using a polyol resin and a hydrolyzable silyl group-contained resin, and which is quite different from a crosslinking style using a conventional polyol resin and melamine resin. However, there are not still sufficiently satisfied hardness, abrasion resistance, water resistance, and solvent resistance.
Since a polyalkyleneglycol di(meth)acrylate forms a flexible thin layer after curing, it is one of exceedingly useful raw materials for employing as an ink and coating, etc. Further, a low molecular weight one is important also as a reactive diluent in an acrylic resin field.
It is to be noted that in the present invention, an acrylate and methacrylate are called a (meth)acrylate, and acrylic acid and methacrylic acid are called a (meth)acrylic acid. However, an acrylic resin and a methacrylic resin are merely called an acrylic resin.
On the other hand, an acrylic resin having carboxylic group (xe2x80x94COOH) is effective for improving adhesion to a material which includes a resin such as a nylon having amino group, and an inorganic compound such as a metal having hydroxyl group and a silica. Further, it is recognized that it is effective for improving a water-solubility and an aqueous alkali solution-solubility of an acylic resin, above all, shortening of developing time of period in an alkali development step and a removing ability of uncured portion in the case of forming a pattern using ultraviolet ray-curability.
For that reason, there is desired a carboxylic group-contained acrylate such as a carboxylic group-contained lactone acrylate, and there has been desired a method for the preparation thereof which is industrially and readily operated.
In a binder for employing as an over-coating for cars, a polymer having hydroxyl group is usually employed in combination with a melamine resin curing agent. However, in a cured thin layer obtained by employing a melamine resin as a curing agent, an acid resistance is usually poor. Accordingly, such the thin layer is apt to be particularly deteriorated by an acidic rain which is recently talked about, resulting in that a problem is caused in an outer appearance.
It is thought that a poor acid resistance in a thin layer obtained by employing a melamine resin as a curing agent is caused by a triazine ring in the melamine resin. Accordingly, so far as a melamine resin is employed as a curing agent, a drawback of the poor acid resistance is not solved.
For example, JP-A-02045577 and JP-A-03287650 Official Gazettes propose a novel coating composition in which a melamine resin is not employed. In the coating composition, since a crosslinking is initiated in an ester bond which is produced by a reaction of an acid group with an epoxy group, an acid resistance is excellent.
However, in the curing system, since functional group concentration is higher and viscosity is high, it is difficult to prepare a high solid type coating having a high solid content, and it is required that a large amount of solvents are employed.
On the other hand, in recent years, there is desired a high solid coating which does not emit a large amount of solvents in circumstances in order to reduce a bad influence to circumstances.
JP-A-06166741 Official Gazette discloses a high solid coating composition in which a silicone polymer is employed. However, in the inventions, in order to introduce a hydroxyl group-functional silicone polymer into a coating composition, an acid-functionalty is given by a reaction with an acid anhydride. As a result, there is caused a drawback that an amount of functional groups cannot be elevated, and Tg is lowered in resins and, Tg cannot be elevated in a coating layer.
On the other hand, JP-B-94041575 Official Gazette discloses a high solid coating composition containing (a) a polyepoxide and (b) a polyester polycarboxylic acid. However, solid content in the coating composition is not high from a viewpoint of not adversely affecting to circumstances, resulting in that a coating layer formed is poor in an acid resistance
Further, in an acid-epoxy curing type coating system, a clear coating layer when being thermally cured remarkably yellows compared to a conventional melamine type coating system, and it is difficult to design a light color such as a white mica color.
As described hereinabove, in recent years, an acrylic-based coating is becoming important in a coating field, and an acrylic-based coating is becoming employed in every fields.
In a conventional lactone modified (meth)acrylate, since distribution of lactone continuous chains becomes broad and the number (n) of continuous chain length becomes large, although a curing reactivity and flexibility are improved, there is occasionally caused a problem of a decline of hardness and acid resistance.
On the other hand, as radically polymerizable unsaturated monomers having carboxylic group, there are known (meth)acrylic acid, itaconic acid, maleic acid, xcex2-(meth)acryloyloxyethyl succinic acid, xcex2-meth)acryloyloxyethyl maleic acid, and xcex2-(meth)acryloyloxyethyl phthalic acid, etc.
The radically polymerizable unsaturated monomers having carboxylic group are employed in exceedingly wide range uses as a raw material and an intermediate for a thermosetting coating, an adhesive, an modifier for processing papers, a crosslinking agent, and a processing agent for fibers, etc., it is required that a kind of the radically polymerizable unsaturated monomers is carefully selected like being appropriate for respective uses.
Generally speaking, as a method for synthesizing a polyester unsaturated monomer having carboxylic group at a terminal, there are known a method in which an xcfx89-hydroxycarboxylic acid is allowed to react with a radically polymerizable unsaturated monomers having carboxylic group, a method in which an xcex1,xcfx89-polyester dicarboxylic acid is allowed to react with a radically polymerizable unsaturated monomers having hydroxyl group, and a method, etc. in which an acid anhydride is allowed to react with a radically polymerizable unsaturated monomers having carboxylic group and an epoxy compound.
However, the methods include a problem that there are largely produced products quite not having a radically polymerizable functinal group or products having two radically polymerizable functinal group as by-products.
Further, as another method, there is a method in which a metal salt of a radically polymerizable unsaturated monomers having carboxylic group, for example, sodium acrylate is allowed to react with an xcfx89-halogenocarboxylic acid, for example, xcex5-chlorocaproic acid.
However, in the methods, an xcfx89-halogenocarboxylic acid which is a raw material is prepared through many steps for the preparation, and a plurality of steps are required for introducing two or more pieces of a radically polymerizable functional groups and, further, there is also required a step for separating a halogenated metal salt by-produced, as a result, an industrial preparation method is not still actualized.
As a method for intending to improve such the drawbacks, for example, JP-A-60067446 proposes a method. In the method, a radically polymerizable unsaturated monomers having carboxylic group is allowed to react with xcex5-caprolactone under the presence of an acidic catalyst to prepare a caprolactone polyester unsaturated monomer, and a fair result is obtained as an industrial method for the preparation. However, an acrylic resin prepared using the monomer often shows tackiness, and it includes a problem as an electric material.
Purpose of the present invention I is to provide a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactone which is employed as an industrial finishing agent (a coating) having a high quality and which is well-balanced in a variety of physical properties in a coating layer, for example, through using as a comonomer in a polymerization reaction with other monomers, and to provide an acrylic polyol resin using the composition.
Purpose of the present invention II is to provide a method for the preparation of the composition.
Purpose of the present invention III is to provide a curable type coating composition in which an acid resistance is elevated even though in a melamine type which is low in price, and which is well-balanced in abrasion resistance and the acid resistance.
Purpose of the present invention IV is to provide a melamine-curable type water-based coating composition which is excellent in hardness, water resistance, restoring resistance, and processability, etc. of a coating layer, and which is excellent for cars, home electric appliances, and cans for beverages and foods.
Purpose of the present invention V is to provide an isocyanate system curable type coating composition which has a sufficient pot-life and, in which a problem of abrasion resistance is solved while maintaining an excellent acid resistance, adhesion, water resistance, and hardness.
Purpose of the present invention VI is to provide an isocyanate system curable type coating composition which has a sufficient pot-life and, in which a problem of abrasion resistance is solved while maintaining excellent acid resistance, adhesion, water resistance, and hardness.
Purpose of the present invention VII is to provide a thermosetting resin composition in which a problem of the above-described acid resistance and odor is solved which are important in a coating for cars, and in which hardness and abrasion resistance, water resistance, and solvent resistance are improved by elevating a crosslinking density, and to provide a top-coat clear coating using the composition.
Purpose of the present invention VIII is to provide an industrially-feasible method for the preparation of a carboxylic group-contained acrylate composition modified by a small amount of lactones.
Purpose of the present invention IX is to provide a high solid curable resin composition in which the above-described problems are solved and, which is capable of forming a thin layer which is excellent in acid resistance to an acid rain, abrasion resistance, yellowing resistance, and outer appearance, and to provide a method for coating (hereinafter, also occasionally referred to as a method for forming a coating layer) using the composition.
Purpose of the present invention X is to provide a polyester unsaturated monomer composition modified by a small amount of lactone which is obtained through an addition reaction of lactone by decreasing lactone chains, which is employed as an industrial finishing agent (a coating) having a high quality which is well-balanced in various physical properties of a coating layer by employing as a comonomer in a polymerization reaction with other monomers, and to provide a method for the preparation thereof, and to provide an acrylic resin using thereof which does not show tackiness so much.
The present inventor, as a result of an intensive investigation for attaining the purpose of the present invention I, found out that the above-described requirements can be satisfied by a hydroxyalkyl(meth)acrylate composition in which there is decreased a proportion of monomers containing two or more continuous chains (nxe2x89xa72) of lactones by allowing to react in a large reaction ratio (the former mol number/the latter mol number) of a hydroxyalkyl(meth)acrylate with respect to a lactone monomer, and the present invention has been completed.
That is, No. 1 in the present invention I provides a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones, in which a proportion of monomers having two or more continuous chains (nxe2x89xa72) of lactones is less than 50% (area % by GPC) which is represented by general formula (1) described below, 
(in the formula, R, R1, R2, and R3 are independently a hydrogen or a methyl group, j is an integer of 2-6, xn pieces of R4 and R5 are independently a hydrogen or an alkyl group having a carbon number of 1-12, xe2x80x9cxxe2x80x9d is 4-7, xe2x80x9cnxe2x80x9d is 0 or an integer of not less than 1, and an average value of xe2x80x9cnxe2x80x9d in the composition is not less than 0.3 to less than 1.0).
Further, No. 2 in the present invention I provides a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in No. 1 of the present invention I, in which the hydroxyalkyl(meth)acrylate is a hydroxyethyl (meth)acrylate.
Still further, No. 3 in the present invention I provides a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in No. 1 of the present invention I, in which the lactone monomer which is employed as a raw material is xcex5-caprolactone and/or valerolactone.
Furthermore, No. 4 in the present invention I provides a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in No. 1 of the present invention I, in which the content of the lactone monomer remained in the composition is 0-10% by weight.
Besides, No. 5 in the present invention I provides a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in No. 1 of the present invention I in which the content of the hydroxyalkyl(meth)acrylate remained in the composition is not less than 20% by weight and not more than 50% by weight.
Also, No. 6 in the present invention I provides a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in No. 1 of the present invention I, in which the content of a di(meth)acrylate which is a by-product in the composition is not more than 2% by weight.
And also, No. 7 in the present invention I provides a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in No. 1 of the present invention I, in which the content of by-products is not more than 10% by weight in the composition, which are produced by side reactions such as a Michaels addition, an acrylic polymerization, a transesterification, and other side reactions.
And also, No. 8 in the present invention I provides a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in any one of Nos. 1-7 of the present invention I, in which the amount of a catalyst to be employed in the ring-opening polymerization for the preparation of the composition is less than 1000 ppm (by weight) based on total amount of materials to be fed.
Also, No. 9 in the present invention I provides a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in any one of Nos. 1-8 of the present invention I, in which a polymerization inhibitor is not more than 1% by weight based on total amount, which is employed for the hydroxyalkyl(meth)acrylate in the ring-opening polymerization for the preparation of the composition.
And also, No. 10 in the present invention I provides an acrylic polyol resin which is obtained using a hydroxyalkyl (meth)acrylate composition modified by a small amount of lactones as described in any one of Nos. 1-9 of the present invention I as a component for polymerization.
The present inventor, as a result of an intensive investigation for attaining the purpose of the present invention II, found out that there can be obtained a lactone-modified hydroxyalkyl(meth)acrylate composition in which lactone continuous chains are decreased by allowing to react a hydroxyalkyl(meth)acrylate with a lactone in a reaction molar ratio of more than 1 (mol number of the former/mol number of the latter), and the present invention has been completed.
That is, No. 1 in the present invention II provides a method for the preparation of a lactone-modified hydroxyalkyl (meth)acrylate composition in which a proportion of monomers having not less than 2 continuous chains (nxe2x89xa72) of lactones is less than 50% by mol (GPC area %), characterized in that a hydroxyalkyl (meth)acrylate is allowed to react with a lactone in a reaction molar ratio of more than 1 in the case of preparing the polylactone-modified hydroxyalkyl(meth)acrylate through allowing to react the hydroxyalkyl(meth)acrylate with a lactone monomer by ring-opening polymerization according to a reaction represented by a general formula (2) described below. 
(in the formula, R, R1, R2, and R3 are independently a hydrogen or a methyl group, xe2x80x9cjxe2x80x9d is an integer of 2-6, xn pieces of R4 and R5 are independently a hydrogen or an alkyl group having a carbon number of 1-12, xe2x80x9cxxe2x80x9d is 4-7, xe2x80x9cnxe2x80x9d is 0 or an integer of not less than 1, and an average value of xe2x80x9cnxe2x80x9d in the composition is not less than 0.3 to less than 1.0).
Further, No. 2 in the present invention II provides a method for the preparation of a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in No. 1 of the present invention II, in which the hydroxyalkyl(meth)acrylate is hydroxyethylacrylate or hydroxyethylmethacrylate.
Still further, No. 3 in the present invention II provides a method for the preparation of a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in No. 1 or 2 of the present invention II, in which the lactone monomer is xcex5-caprolactone and/or valerolactone.
Furthermore, No. 4 in the present invention II provides a method for the preparation of a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in any one of Nos. 1-3 of the present invention II in which an average value of n is not less than 0.35 and not more than 1.0.
Besides, No. 5 in the present invention II provides a method for the preparation of a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in any one of Nos. 1-3 of the present invention II, in which the content of the lactone monomer remained in the composition is 0-10% by weight.
Also, No. 6 in the present invention II provides a method for the preparation of a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in any one of Nos. 1-3 of the present invention II in which the content of the hydroxyalkyl(meth)acrylate remained in the composition is not less than 20% by weight and not more than 50% by weight.
And also, No. 7 in the present invention II provides a method for the preparation of a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in any one of Nos. 1-3 of the present invention II, in which the content of a di(meth)acrylate which is a by-product in the composition is not more than 2% by weight.
And also, No. 8 in the present invention II provides a method for the preparation of a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in any one of Nos. 1-3 of the present invention II, in which the content of by-products is not more than 10% by weight in the composition, which are produced by side reactions such as a Michaels addition, an acrylic polymerization, a transesterification, and other side reactions.
And also, No. 9 in the present invention II provides a method for the preparation of a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in any one of Nos. 1-8 of the present invention II, in which the amount of a catalyst to be employed in the reaction of the lactone with the hydroxyalkyl(meth)acrylate is less than 1000 ppm (by weight) based on total amount of materials to be fed.
And also, No. 10 in the present invention II provides a method for the preparation of a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones as described in any one of Nos. 1-9 of the present invention II, in which the content of an inhibitor in polymerization of the hydroxyalkyl(meth)acrylate with the lactones is not more than 1% by weight based on total amount of materials to be fed.
The present inventor, as a result of an intensive investigation for attaining the purpose of the present invention III, found out that the above-described requirement can be satisfied by a curable resin composition containing 0.5-80 parts by weight of an acrylic polyol resin (A) obtained using a hydroxyalkyl(meth)acrylate composition (a) in which a proportion of monomers having not less than 2 continuous chains (nxe2x89xa72) of lactones is decreased and 0.5-50 parts by weight of a melamine resin (III-B) as essential components, and the present invention has been completed.
That is, No. 1 in the present invention III provides a curable resin composition containing 0.5-80 parts by weight of an acrylic polyol resin (A) obtained using a hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones in which a proportion of monomers having not less than 2 continuous chains (nxe2x89xa72) of lactones is less than 50% (GPC area %) as polymerizing components and 0.5-50 parts by weight of a melamine resin (B) [total of the (A) and (B) does not exceed 100 parts by weight].
Further, No. 2 in the present invention III provides a curable resin composition as described in No. 1 of the present invention III, in which the hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones is obtained using a hydroxyethyl(meth)acrylate.
Still further, No. 3 in the present invention III provides a curable resin composition as described in No. 1 or 2 of the present invention III, in which the hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones is obtained using xcex5-caprolactone, xcex4-valerolactone, xcex3-butyrolactone, or a mixture thereof as lactone monomers.
Besides, No. 4 in the present invention III provides a curable resin composition as described in any one of Nos. 1-3 of the present invention III, in which the acrylic polyol resin (A) is composed of 5-70 parts by weight of the hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones, 0-90 parts by weight of an alkyl(meth)acrylate having a carbon number of 1-20, 0-30 parts by weight of a (meth)acrylic acid, and 0-40 parts by weight of other polymerizable unsaturated monomer.
Also, No. 5 in the present invention III provides a curable resin composition as described in any one of Nos. 1-4 of the present invention III, in which the acrylic polyol resin (A) has a hydroxyl group value of 5-250 and a number average molecular weight of 3,000-300,000.
The present inventor, as a result of an intensive investigation for attaining the purpose of the present invention IV, found out that the above-described problems can be solved by using a melamine-curable type water-based coating composition composed of an acrylic polyol resin (A) obtained by a specified hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones and an amino-plasto resin (B), and the present invention has been completed.
That is, No. 1 in the present invention IV provides a melamine-curable type water-based coating composition containing 5-30 parts by weight of an acrylic polyol resin (A) obtained using a hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones represented by the above-described general formula (1), in which a proportion of monomers having not less than 2 continuous chains (nxe2x89xa72) of lactones is less than 50% (GPC area %) as polymerizing components and 10-60 parts by weight of an amino-plasto resin (IV-B).
No. 2 in the present invention IV provides a melamine-curable type water-based coating composition as described in No. 1 of the present invention IV, characterized in that the acrylic polyol resin (A) is composed of (i) 3-40% by weight of the hydroxyalkyl (meth)acrylate composition (a) modified by a small amount of lactones, (ii) 1-20% by weight of xcex1,xcex2-unsaturated carboxylic acid, (iii) 1-25% by weight of an N-alkoxymethyl(meth)acrylate having a carbon number of 1-6 in an alkyl group, and (iv) an aromatic vinyl monomer and an alkyl(meth)acrylate which are contained in an amount that 100% by weight minus the total weight of the above components (i), (ii), and (iii).
No. 3 in the present invention IV provides a melamine-curable type water-based coating composition as described in No. 1 or 2 of the present invention IV, in which the acrylic polyol resin (A) has a number average molecular weight of 2,000-50,000, a hydroxyl group value of 10-150, and a Tg point of 0-60xc2x0 C.
No. 4 in the present invention IV provides a melamine-curable type water-based coating composition as described in any one of Nos. 1-3 of the present invention IV, in which the amino-plasto resin (IV-B) is at least one of a melamine resin (j), a guanamine resin (k) selected from benzoguanamine, spyroguanamine, acetoguanamine, and phthaloguanamine, and/or a melamine-guanamine cocondensed resin (l).
No. 5 in the present invention IV provides a melamine-curable type water-based coating composition as described in any one of Nos. 1-4 of the present invention IV, which is employed for cars, home electric appliances, and cans for beverages and foods.
The present inventors, as a result of an intensive investigation for attaining the purpose of the present invention V, found out that the above-described requirement can be satisfied by a curable resin composition essentially containing 50-90 parts by weight of an acrylic polyol resin (A) obtained using a hydroxyalkyl(meth)acrylate composition (a) in which a proportion of monomers having not less than 2 continuous chains (nxe2x89xa72) of lactones is reduced and which is obtained by a large reaction molar ratio of a hydroxyalkyl(meth)acrylate with lactone monomers (the former mol number/the latter mol number), and 10-50 parts by weight of a polyisocyanate compound (V-B), and the present invention has been completed.
That is, No. 1 in the present invention V provides a curable resin composition containing 50-90 parts by weight of an acrylic polyol resin (V-A) obtained using a hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones which is represented by the above-described general formula (1) in which a proportion of monomers having not less than 2 continuous chains (nxe2x89xa72) of lactones is less than 50% (GPC area %) as polymerizing components and 50-10 parts by weight of a polyisocyanate compound (V-B) [total of the (V-A) and (V-B) does not exceed 100 parts by weight].
No. 2 in the present invention V provides a curable resin composition as described in No. 1 of the present invention V, in which the acrylic polyol resin (V-A) is composed of 5-65% by weight of the hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones, 0-30% by weight of a vinyl monomer having hydroxyl group, 0.1-20% by weight of a polyester resin having a copolymerizable unsaturated group, and other vinyl monomers (residual weight).
The present inventor, as a result of an intensive investigation for attaining the purpose of the present invention VI, found out that the above-described requirement can be satisfied by a curable resin composition essentially containing 0.5-80 parts by weight of an acrylic polyol resin (A) obtained using a hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones, and which is obtained by a large reaction molar ratio of a hydroxyalkyl(meth)acrylate with lactone monomers (the former mol number/the latter mol number), and in which a proportion of monomers having not less than 2 continuous chains (nxe2x89xa72) of lactones is reduced, and 0.5-50 parts by weight of a polyisocyanate compound (C), and the present invention has been completed.
That is, No. 1 in the present invention VI provides a curable resin composition containing 0.5-80 parts by weight of an acrylic polyol resin (VI-A) having carboxylic group and a functional group obtained by allowing to react a hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones represented by the general formula (1) described in claim 1 in which a proportion of monomers having not less than 2 continuous chains (nxe2x89xa72) of lactones is less than 50% (GPC area %) with a vinyl monomer having carboxylic group and other vinyl monomers, and 0.5-50 parts by weight of a polyisocyanate compound (VI-B) [total of the (VI-A) and (VI-B) does not exceed 100 parts by weight] as essential components.
Further, No. 2 of the present invention VI provides a curable resin composition as described in No. 1 of the present invention VI, in which the acrylic polyol resin (VI-A) is a vinyl copolymer having carboxylic group and a functional group obtained by allowing to react a reaction product of a hydroxyl group-contained resin obtained by copolymerizing a hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones with a (meth)acrylic anhydride, and then, by allowing to react the reaction product with a vinyl-based monomer having carboxylic group and other vinyl-based monomers.
Still further, No. 3 of the present invention VI provides a curable resin composition as described in No. 2 of the present invention VI, in which the acrylic polyol resin (VI-A) is a resin obtained using the hydroxyl group-contained resin in the No. 2 of the present invention VI and at least one selected from a urethane resin having hydroxyl groups, an epoxy resin having hydroxyl groups, a cellulose derivative having hydroxyl groups, and a polyester resin having hydroxyl groups as the resin having hydroxyl groups.
Furthermore, No. 4 of the present invention VI provides a curable resin composition as described in No. 2 of the present invention VI, in which the acrylic polyol resin (VI-A) is a resin obtained using the hydroxyl group-contained resin in the No. 2 of the present invention VI and a urethane resin having hydroxyl groups as the resin having hydroxyl groups.
Besides, No. 5 in the present invention VI provides a curable resin composition as described in any one of Nos. 1-4 of the present invention VI, in which the polyisocyanate compound (VI-B) is a polyisocyanate compound containing an epoxy resin.
Also, No. 6 in the present invention VI provides a curable resin composition as described in any one of Nos. 1-5 of the present invention VI, in which the hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones is a product obtained using hydroxyethyl(meth)acrylate.
And also, No. 7 of the present invention VI is a coating characterized by containing (i) crosslinked particles obtained by dispersing a mixture of the acrylic polyol resin (VI-A) with the polyisocyanate compound (VI-B) into a water-based medium and by crosslinking thereof, or (ii) composite-type crosslinked particles composed of a urethane-urea/ethylene-based resin obtained through polymerizing polymerizable ethylene-based unsaturated compounds containing the hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones in water in which crosslinked urethane-urea particles are dispersed, as resin components for forming a thin layer.
And also, No. 8 of the present invention VI is a coating as described in No. 7 of the present invention VI characterized by containing more than 50% by weight of crosslinked particles having particle diameter of not more than 1 m and, moreover, an average molecular weight between crosslinking points of a range of 300-2,000, as resin components for forming a thin layer.
And also, No. 9 of the present invention VI is a coating as described in No. 7 or 8 of the present invention VI, in which the crosslinked particles have a thin layer-formable temperature of not more than 100xc2x0 C.
And also, No. 10 of the present invention VI is a coating as described in any one of Nos. 7-9 of the present invention VI, in which the content of the crosslinked particles is not less than 70% in the resin components for forming a thin layer.
And also, No. 11 of the present invention VI is a coating as described in any one of Nos. 7-10 of the present invention VI, characterized by containing 1-25% by weight of a crosslinking agent together with the crosslinked particles as the resin components for forming a thin layer.
And also, No. 12 of the present invention VI is a coating as described in any one of Nos. 7-11 of the present invention VI, characterized by further containing a thin layer-formable resin having a reactive group other than the crosslinked particles as the resin components for forming a thin layer.
And also, No. 13 of the present invention VI is a coating as described in any one of Nos. 7-12 of the present invention VI, in which the crosslinked particles contain pigments in an inside thereof.
The present inventor, as a result of an intensive investigation for attaining the purpose of the present invention VI, found out that the problems can be solved by using a curable resin composition which comprises an acrylic polyol resin (VII-A) having hydroxyl groups composed of a hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones which has hydroxyl group at a terminal, and an acrylic copolymer (VII-B) having an alkoxysilyl group, and the present invention has been completed.
That is, No. 1 in the present invention VII provides a thermosetting resin composition which contains at least 2-50 parts by weight of an acrylic polyol resin (VII-A) containing a hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones represented by the general formula (1) in which a proportion of monomers having not less than 2 continuous chains (nxe2x89xa72) of lactones is less than 50% (GPC area %) as a polymerizable component, and 30-80 parts by weight of an acrylic copolymer (VII-B) having an alkoxysilyl group [total of the (VII-A) and (VII-B) does not exceed 100 parts by weight], as polymerizable components.
No. 2 of the present invention VII provides a thermosetting resin composition as described in No. 1 of the present invention VII, in which the acrylic polyol resin (VII-A) further has at least one kind selected from an acid anhydride group, an epoxy group, amino group, and carboxylic group.
No. 3 of the present invention VII provides a thermosetting resin composition as described in No. 1 or 2 of the present invention VII, in which the acrylic copolymer (VII-B) having an alkoxysilyl group has a group represented by general formula (VII-3) described below, 
(in the formula, R6 represents an alkyl group having a carbon number of 1-10, R7 and R8 are a hydrogen atom or a monovalent hydrocarbon group selected from an alkyl group, an aryl group, and an aralkyl group which have a carbon number of 1-10, xe2x80x9caxe2x80x9d is the number of a substituted group, and it represents an integer of 0, 1, or 2).
No. 4 of the present invention VII provides a thermosetting resin composition as described in No. 3 of the present invention VII, in which the acrylic copolymer (VII-B) having an alkoxysilyl group further has at least one kind selected from an acid anhydride group, an epoxy group, amino group, and carboxylic group.
No. 5 of the present invention VII provides a thermosetting resin composition as described in No. 3 or 4 of the present invention VII, in which the acrylic copolymer (VII-B) having an alkoxysilyl group has a number average molecular weight of 1,000-30,000.
No. 6 of the present invention VII provides a thermosetting resin composition as described in any one of Nos. 3-5 of the present invention VII, in which the acrylic copolymer (VII-B) having an alkoxysilyl group contains 5-90% by weight of an alkoxysilyl group-contained monomer (VII-b) having a polymerizable unsaturated double bond as a polymerizing component.
No. 7 of the present invention VII provides a thermosetting resin composition containing 0.1-20 parts by weight of a catalyst (VII-C) for curing based on 100 parts by weight of the thermosetting resin composition as described in any one of Nos. 1-6 of the present invention VII.
No. 8 of the present invention VII provides a thermosetting resin composition as described in No. 7 of the present invention VII, in which the catalyst (VII-C) for curing is an organic tin compound, an acidic phosphate, a mixture or a reaction product of the acidic phosphate with an amine, a saturated or unsaturated polycarboxylic acid, a saturated or unsaturated polycarboxylic anhydride, a reactive silicone compound, an organic titanate compound, an organic aluminum compound, or a mixture thereof.
No. 9 of the present invention VII provides a top coat clear coating essentially containing a thermosetting resin composition as described in Nos. 1-8 of the present invention VII.
The present inventor, as a result of an intensive investigation for attaining the purpose of the present invention VIII, found out that there can be industrially and advantageously prepared a carboxylic group-contained acrylate monomer modified by small amount of lactones by allowing to react a hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones which has hydroxyl group at a terminal with a carboxylic acid or an anhydride thereof, and the present invention has been completed.
That is, No. 1 of the present invention VIII provides a method for the preparation of a carboxylic group-contained acrylate composition (axe2x80x2) modified by a small amount of lactones represented by a general formula (VIII-3) described below by allowing to react the hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones represented by the above-described general formula (1) in which a proportion of monomers having not less than 2 continuous chains (nxe2x89xa72) of lactones is less than 50% (GPC area %) with a carboxylic acid or anhydride (VIII-b) thereof represented by a general formula (VIII-2) described below, 
(in the formula, R, R1, R2, and R3 are independently a hydrogen or a methyl group, xe2x80x9cjxe2x80x9d is an integer of 2-6, xn pieces of R4 and R5 are independently a hydrogen atom or an alkyl group having a carbon number of 1-12, xe2x80x9cxxe2x80x9d is 4-7, xe2x80x9cnxe2x80x9d is 0 or an integer of not less than 1, an average value of xe2x80x9cnxe2x80x9d in the composition is not less than 0.3 to less than 1.0, R9 is a residual group of a carboxylic acid, and xe2x80x9cmxe2x80x9d is an integer of 1-3).
No. 2 of the present invention VIII provides a method for the preparation of a carboxylic group-contained acrylate composition (axe2x80x2) modified by a small amount of lactones as described in No. 1 of the present invention VIII, characterized in that a reaction of the hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones with the carboxylic acid or anhydride (VIII-b) thereof is conducted at a range of 40-160xc2x0 C.
No. 3 of the present invention VIII provides a method for the preparation of a carboxylic group-contained acrylate composition (axe2x80x2) modified by a small amount of lactones as described in No. 1 or 2 of the present invention VIII, characterized in that a reaction of the hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones with the carboxylic acid or anhydride thereof (VIII-b) is conducted under the presence of oxygen and a polymerization inhibitor.
No. 4 of the present invention VIII provides a method for the preparation of a carboxylic group-contained acrylate composition (axe2x80x2) modified by a small amount of lactones as described in any one of Nos. 1-3 of the present invention VIII, characterized in that 0.9-1.1 mol of the carboxylic acid or anhydride (VIII-b) thereof is allowed to react with 1 mol of the hydroxy(meth)acrylate composition (a) modified by a small amount of lactones.
The present inventor found out that the purpose of the present invention IX can be attained by using a resin composition comprising an acrylic polycarboxylic acid resin (Axe2x80x2) containing a carboxylic group-contained acrylate composition (axe2x80x2) modified by a small amount of lactones as a polymerizing component and a polyoxide (IX-B), and the present invention has been completed.
That is, No. 1 of the present invention IX provides a curable resin composition comprising 10-70 parts by weight of an acrylic polycarboxylic acid resin (Axe2x80x2) containing the carboxylic group-contained acrylate composition (axe2x80x2) modified by a small amount of lactones represented by the above-described general formula (VIII-3) in which a proportion of monomers having not less than 2 continuous chains (nxe2x89xa72) of lactones is less than 50% (GPC area %) as a polymerizing component and 10-80 parts by weight of a polyepoxide (IX-B).
No. 2 of the present invention IX provides a curable resin composition as described in No. 1 of the present invention IX, characterized in that the carboxylic group-contained hydroxy(meth)acrylate composition (axe2x80x2) modified by a small amount of lactones is obtained by allowing to react the hydroxyalkyl(meth)acrylate composition modified by a small amount of lactones represented by the above-described general formula (1) in which a proportion of monomers having not less than 2 continuous chains (nxe2x89xa72) of lactones is less than 50% (GPC area %) with the carboxylic acid or the anhydride thereof represented by the above-described general formula (VIII-2).
No. 3 of the present invention IX provides a curable resin composition as described in No. 2 of the present invention IX, characterized in that the carboxylic group-contained hydroxy(meth)acrylate composition (axe2x80x2) modified by a small amount of lactones is obtained by allowing to react 0.9-1.1 mol of the carboxylic acid or the anhydride thereof with respect to 1 mol of the hydroxy(meth)acrylate composition (a) modified by a small amount of lactones.
No. 4 of the present invention IX provides a curable resin composition as described in any one of Nos. 1-3 of the present invention IX, characterized in that the acrylic polycarboxylic acid resin (Axe2x80x2) is a copolymer of 5-80% by weight of a carboxylic group-contained ethylenic unsaturated monomer with 20-95% by weight of an ethylenic unsaturated monomer not having carboxylic group, provided that the ratio of the carboxylic group-contained hydroxy(meth)acrylate composition (axe2x80x2) modified by a small amount of lactones is 5-50% by weight in the acrylic polycarboxylic acid resin (Axe2x80x2), and the copolymer has at least two carboxylic groups on average in the molecule and an acid value of 5-300 mg KOH/g-solid and a number average molecular weight of 500-8000.
No. 5 of the present invention IX provides a curable resin composition as described in any one of Nos. 1-4 of the present invention IX, characterized in that terminal carboxylic groups in the acrylic polycarboxylic acid resin (Axe2x80x2) are an acrylic polycarboxylic acid resin (bAxe2x80x2) blocked by a blocking group which can discharge carboxylic groups by heat and/or water.
No. 6 of the present invention IX provides a curable resin composition as described in any one of Nos. 1-5 of the present invention IX, characterized in that the polyepoxide (IX-B) is an acrylic polyepoxide having an epoxy equivalent of 50-700 and a number average molecular weight of 200-10000.
No. 7 of the present invention IX provides a curable resin composition as described in any one of Nos. 1-6 of the present invention IX, characterized in that the polyepoxide (IX-B) is a polyepoxide having hydroxyl group and an epoxy group which is obtained by copolymerization of 5-70% by weight of (i) a hydroxyl group-contained ethylenic unsaturated monomer having a structure represented by a formula (4) described below with 10-60% by weight of (ii) an epoxy group-contained ethylenic unsaturated monomer and optionally 0-85% by weight of (iii) an ethylenic unsaturated monomer not having an epoxy group, 
[in the formula, R is a hydrogen atom or a methyl group, and X is an organic chain shown by formula (5) described below,
xe2x80x94Oxe2x80x94Yxe2x80x94(OCOxe2x80x94(CH2)mxe2x80x94)qxe2x80x94xe2x80x83xe2x80x83(5) 
(in the formula, Y is a linear or branched alkylene group having a carbon number of 2-8, xe2x80x9cmxe2x80x9d is an integer of 3-7, and xe2x80x9cqxe2x80x9d is an integer of 0-4),
or an organic chain shown by formula (6) described below, 
(in the formula, R is a hydrogen atom or a methyl group, and n is an integer of 2-50)].
No. 8 of the present invention IX provides a curable resin composition as described in any one of Nos. 1-7 of the present invention IX, and which further contains 0.1-10 parts by weight of an antioxidant (IX-C).
No. 9 of the present invention IX provides a curable resin composition as described in any one of Nos. 1-8 of the present invention IX, and which further contains 5-70 parts by weight of a polyester polycarboxylic acid (IX-D) having an acid value of 30-350 mg-KOH/g-solid.
No. 10 of the present invention IX provides a curable resin composition as described in any one of Nos. 1-9 of the present invention IX, and which further contains 0.1-10 parts by weight of crosslinked resin particles (IX-E).
No. 11 of the present invention IX provides a clear coating composition containing a curable resin composition as described in any one of Nos. 1-10 of the present invention IX as a binder.
No. 12 of the present invention IX provides a method for coating which includes a step in which a water-based or a solvent-based base coating is coated on a substrate coated by under-coating or internally-coating; a step in which a clear coating composition of No. 1 in the present invention IX is coated on the base coating layer without curing; and a step in which a layer of the base coating and a layer of the clear coating are cured by heating.
In the above descriptions, part is part by weight.
The present inventor, as a result of an intensive investigation for attaining the purpose of the present invention X, found out that the above-described requirement can be satisfied by a polyester unsaturated monomer composition modified by a small amount of lactones, in which a proportion of monomers having not less than 2 continuous chains (nxe2x89xa72) of lactones is decreased by a large reaction molar ratio (the former mol number/the latter mol number) of a carboxylic group-contained polymerizable unsaturated monomer, and the present invention has been completed.
That is, No. 1 of the present invention X provides a polyester unsaturated monomer composition modified by a small amount of lactones, in which a proportion of monomers having not less than 2 continuous chains (nxe2x89xa72) of lactones is less than 50% (GPC area %) with respect to total of polymerizable unsaturated monomers containing carboxylic group, and which are obtained by a ring-opening polymerization of a lactone monomer.
No. 2 of the present invention X provides a polyester unsaturated monomer composition modified by a small amount of lactones as described in No. 1 of the present invention X, in which the polymerizable unsaturated monomers containing carboxylic group are at least one kind selected from a group consisting of a (meth)acrylic acid, itaconic acid, xcex2-(meth)acryloyloxyethyl succinic acid, xcex2-(meth)acryloyloxyethyl maleic acid, xcex2-(meth)acryloyloxyethyl phthalic acid, maleic acid, a monoalkyl maleate (a carbon number in an alkyl group is 1-12), tetrahydrophthalic acid, and an anhydride thereof.
No. 3 of the present invention X provides a polyester unsaturated monomer composition modified by a small amount of lactones as described in No. 2 of the present invention X, in which the polymerizable unsaturated monomers containing carboxylic group are a (meth)acrylic acid, and which is obtained by a reaction represented by formula (11) described below, 
(in the formula, R and R1 are independently a hydrogen atom or a methyl group, xn pieces of R4 and R5 are independently a hydrogen atom or an alkyl group having a carbon number of 1-12, xe2x80x9cxxe2x80x9d is 4-7, xe2x80x9cnxe2x80x9d and xe2x80x9cnxe2x80x9d in the composition are 0 or an integer of not less than 1, and an average value of xe2x80x9cnxe2x80x9d in the composition is not less than 0.3 to less than 1.0).
No. 4 of the present invention X provides a polyester unsaturated monomer composition modified by a small amount of lactones as described in any one of Nos. 1-3 of the present invention X, in which the lactone monomer is a lactone having 5, 6, 7 and/or 8-members ring.
No. 5 of the present invention X provides a polyester unsaturated monomer composition modified by a small amount of lactones as described in any one of Nos. 1-4 of the present invention X, in which the lactone monomer is xcex5-caprolactone and/or valerolactone.
No. 6 of the present invention X provides a polyester unsaturated monomer composition modified by a small amount of lactones as described in any one of Nos. 1-5 of the present invention X, characterized in that the proportion of monomers having not less than 2 continuous chains (nxe2x89xa72) of lactones is less than 40% (GPC area %).
No. 7 in the present invention I provides a polyester unsaturated monomer composition modified by a small amount of lactones as described in any one of Nos. 1-6 of the present invention X, in which the content of residual lactone monomers is 0-10% by weight.
No. 8 in the present invention X provides a polyester unsaturated monomer composition modified by a small amount of lactones as described in any one of Nos. 1-7 of the present invention X, in which the content of the residual polymerizable unsaturated monomers containing carboxylic group is more than 20% by weight and not more than 50% by weight.
No. 9 in the present invention X provides a polyester unsaturated monomer composition modified by a small amount of lactones as described in any one of Nos. 1-8 of the present invention X, in which the content of a di(meth)acrylate of the polymerizable unsaturated monomers containing carboxylic group which is a by-product is not more than 2% by weight.
No. 10 in the present invention X provides a polyester unsaturated monomer composition modified by a small amount of lactone as described in any one of Nos. 1-9 of the present invention X, in which the content of by-products produced by side reactions such as a Michaels addition, an acrylic polymerization, a transesterification, and other side reactions is not more than 10% by weight.
No. 11 in the present invention X provides a polyester unsaturated monomer composition modified by a small amount of lactone as described in any one of Nos. 1-10 of the present invention X, in which the amount of a catalyst to be employed in the ring-opening polymerization is less than 1000 ppm by weight based on total amount of materials to be fed.
No. 12 in the present invention X provides a polyester unsaturated monomer composition modified by a small amount of lactone as described in any one of Nos. 1-11 of the present invention X, in which a polymerization inhibitor is not more than 1% by weight based on total amount to be fed, which is employed for a (meth)acrylic acid in the ring-opening polymerization.
No. 13 in the present invention X provides a method for the preparation of a polyester unsaturated monomer composition modified by a small amount of lactone, in which 0.3-less than 1.0 mol of a lactone monomer is polymerized by ring-opening with respect to 1 mol of a radically polymerizable unsaturated monomers containing carboxylic group, and a proportion of monomers having not less than 2 continuous chains (nxe2x89xa72) of lactones is adjusted to less than 50%.
No. 14 in the present invention X provides a method for the preparation of a polyester unsaturated monomer composition modified by a small amount of lactone as described in No. 13 of the present invention X, in which an acidic catalyst is a Lewis acid or a Br nsted acid.
No. 15 in the present invention X provides an acrylic resin using a polyester unsaturated monomer composition modified by a small amount lactone as described in any one of Nos. 1-12 of the present invention X.
No. 16 in the present invention X is a method for the preparation of polyester unsaturated monomer composition modified by a small amount of lactone, characterized in that 0.3-less than 1.0 mol of a lactone monomer is polymerized by ring-opening with respect to 1 mol of a radically polymerizable unsaturated monomers containing carboxylic group using a stannous halide, monobutyltin tris-2-ethylhexanate, stannous octoate, dibutyltin dilaurate, or a mixture thereof as a catalyst, followed by separating unreacted radically polymerizable unsaturated monomers containing carboxylic group.
No. 17 in the present invention X is a method for the preparation of a polyester unsaturated monomer composition modified by a small amount of lactone as described in claim 12, in which the catalyst to be employed in the ring-opening polymerization is less than 1000 ppm by weight based on total amount of materials to be fed.
By the present invention, there can be prepared a polyester unsaturated monomer modified by a small amount of lactone having the same number of a radically polymerizable functional group as in the radically polymerizable unsaturated monomer having carboxylic group which is employed as a raw material, and in which an average addition amount of lactones is 0.35 to not more than 1.0 mol.
Particularly, in the case that there are employed, for example, acrylic acid and methacrylic acid as the radically polymerizable unsaturated monomer having carboxylic group, there can be prepared the polyester unsaturated monomer modified by a small amount of lactone which essentially contains 1 piece of a radically polymerizable functional group without producing a compound not having a radically polymerizable functional group at all and a compound having two or more pieces of a radically polymerizable functional group.
The polyester unsaturated monomer modified by a small amount of lactone obtained has a reactive carboxylic group at one terminal thereof and, further, it has a feature that there is a radically polymerizable unsaturated group at a position which exists far apart from the carboxylic group.
Further, in the acrylic resin composition using the polyester unsaturated monomer modified by a small amount of lactone of the present invention, since tackiness can be removed by elevating Tg of the resin composition, it is particularly useful in an electric material field, etc.